Re: [PATCH v7 20/25] ACPI / APEI: Use separate fixmap pages for arm64 NMI-like notifications

Borislav Petkov
2019-01-31T13:39:00Z

On Wed, Jan 23, 2019 at 06:33:02PM +0000, James Morse wrote:
> Was the best I had, but this trips the BUILD_BUG() too early.
> With it, x86 BUILD_BUG()s. With just the -1 the path gets pruned out, and there
> are no 'sdei' symbols in the object file.
>
> ...at this point, I stopped caring!

Yah, you said it: __end_of_fixed_addresses will practically give you the
BUG behavior:

if (idx >= __end_of_fixed_addresses) {
BUG();
return;
}

and ARM64 does the same.

> We already skip registering notifiers if the kconfig option wasn't selected.
>
> We can't catch this at compile time, as the dead-code elimination seems to
> happen in multiple passes.
>
> I'll switch the SDEI ones to __end_of_fixed_addresses, as both architectures
> BUG() when they see this.

Right.

Thx.

--
Regards/Gruss,
Boris.

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